WO2008015410A1

WO2008015410A1 - Stabiliser for builders' trestles

Info

Publication number: WO2008015410A1
Application number: PCT/GB2007/002895
Authority: WO
Inventors: Liam Clear
Original assignee: Safestand Limited
Priority date: 2006-07-31
Filing date: 2007-07-31
Publication date: 2008-02-07
Also published as: GB2441537A; GB0615214D0

Abstract

A stabilising prop 10 for a builders' trestle 14 has an end 2 attachable to the trestle and another end 3 engageable with the ground. The length of the prop between the ends is adjustable so that in use the prop may be attached to the trestle extending outwardly of a load bearing base 16 of the trestle and braced between the trestle and the ground. In this way, the prop 10 may act to increase the overturning moment of the trestle and enhance its stability.

Description

STABILISERFORBUILDERS' TRESTLES

Field of Invention

The present invention relates to builders' trestles, more particularly to builders' trestle stabilisers.

Introduction

It is common for workmen such as builders or decorators to use access platforms formed from scaffolding boards or staging supported at an elevated level using a line of two or more adjustable steel trestles commonly known as bandstands. Each trestle comprises a pair of vertical supports connected by a cross member upon which the boards can be supported to make the platform. The vertical supports are telescopically received in tubular uprights forming the sides of a base frame. The uprights have feet attached to their lower ends, extending transverse to the cross member to provide standing stability for the trestle. As the working height of the trestles increases, particularly near to the maximum extension of the vertical supports, the stability provided by the feet may not be sufficient and there is the risk of the trestle toppling over. Furthermore the feet only provide "in line" stability, i.e. stability along, the length of the boards making up the platform. Standard bandstands are relatively narrow, typically only four scaffolding boards wide. When used at or near their fully extended height and/or on uneven ground, they can be unstable in the length direction of the cross member. They are therefore sometimes overturned by sudden movements of the workmen or uneven loading of the platform. The feet do not enhance stability against movement axially of the cross member. Thus there is a need to make builders' trestles more stable and safer.

Known techniques for providing additional stability to builder's trestles involve pivotally mounting an auxiliary stabiliser leg to the base member uprights and securing the stabiliser in a set extended position by a cross-brace which is fixed between the vertical support member and the stabiliser. Another known auxiliary stabiliser consists of a rigid framework attachable to the trestle upright and providing a ground engaging foot extending outwards to one side of the platform: see for example GB2364733, particularly Figure 3. Although such stabilisers provide adequate stability to builders' trestles, they suffer from the disadvantage that they require tools and clamps to secure them in place. When there are a number of stabilisers to be assembled this can be time consuming. In addition, the number of moving parts in the stabiliser increases the cost of manufacture. The time, effort and cost may inhibit them being used, despite safety concerns.

US 6761249 concerns a support that may be used as a trestle, a table or as a stepladder. The support comprises a frame having three or four foldable and/or telescopically adjustable weight bearing legs. These provide convenience in storage and handling, as well as allowing the support to stand firmly on uneven ground. There is no disclosure of a height- adjustable cross member above the frame, for supporting a work platform formed from scaffolding boards or the like. Nor is there disclosure of any auxiliary stabilising means used in addition to the weight bearing legs.

Summary of the Invention

According to the present invention the above problems are mitigated by providing an auxiliary stabilising prop for a builders' trestle, having an end attachable to the trestle and another end engageable with the ground t so that in use the prop may be attached to the trestle extending outwardly of a load bearing base, of the trestle and braced between the trestle and the ground, characterised in that the length of the prop between the ends is adjustable. In this way, the prop may act to increase the overturning moment of the trestle and enhance its stability.

The direction in which the prop extends may be selected so as to enhance the trestle stability in that direction. For example, the prop may extend transversely to the trestle cross member so as to improve the "in line" stability of the platform. On the other hand, the prop can equally be used extending outwardly to one side of the platform beyond an end of the cross memberto improve the platform's lateral stability.

The ground engageable end of the prop may comprise a foot, preferably a load spreading pad to provide increased resistance against the prop sinking into soft ground. The foot may be at a suitable fixed angle for engagement with the ground or may be adjustably mounted, for example pivotable, with respect to the rest of the prop so that it can squarely engage the ground.

Preferably the length of the prop is telescopically adjustable. Inner and outer parts of the telescopic mechanism may be selectively secured together in a variety of relative longitudinal positions by releasable locking means. For example the releasable locking means may comprise a latch member secured to one of the inner or outer parts, and receivable in any selected one of a series of detents provided in the other of the inner or outer parts. In a particular embodiment, the latch member may be a spring loaded ball or pin attached to one part, and the detents a series of apertures formed in the other part.

The upper end of the prop is preferably attachable to the trestle by a spigot and socket connection. For example a downwardly and outwardly angled socket can be-attached (e.g. welded) to the trestle at a suitable position for reception of the prop upper end. Of course it is equally possible for the disposition of the spigot and socket to be reversed; a spigot being attached to the trestle for reception within a hollow upper end of the prop. The spigot and socket are conveniently interengageable by axial movement of the prop. Preferably the .spigot is secured in the socket by releasable latch means, for example a spring loaded ball or . pin attached to one of the spigot or socket and engageable with a detent such as a hole provided in the other of the spigot or socket.

This provides the advantage that the prop can be easily and quickly installed and adjusted without the use of any tools. It has been found that for most purposes the prop is sufficiently strong and secure without the need for a cross brace. This makes its manufacture and installation particularly simple. However, in particularly demanding applications a cross brace (e.g. a rod, tube, chain or cable) can be provided between the prop and the trestle, above the prop length adjustment means. The cross brace may be latched to the trestle, so as again to obviate the use of tools for its installation.

Further preferred features and aspects of the present invention will be apparent from the claims and the following illustrative description made with reference to the accompanying drawings. Brief Description of the Drawings.

Figure 1 is a front perspective view of a builder's trestle with two attached props embodying the present invention.

Figure 2 is an enlarged view of the right hand prop shown in Figure 1, together with its attachment socket on the trestle.

Figure 3 is a further enlarged view of the attachment socket.

Figure 4 is an enlarged view of the upper end and middle section of the prop shown in

Figures 1 and 2.

Figure 5 is a cross-sectional view schematically showing the telescopic mechanism latch pin and detent aperture.

Figure 6 shows a modification of the embodiment of the preceding Figures.

Detailed Description of the Invention

The two stabilisers 10 shown in Figure 1. are secured to respective tubular uprights 12 of a builders' trestle 14. The uprights 12 form the sides of a base frame for the trestle 14. The trestle further comprises a height adjustable cross member 18 that is used to support a platform at an elevated level. A pair of vertical support members (not visible in Figure 1) depend from the cross member and are telescopically received within the uprights 12. A pair of locking pins 22 is captively slidable on an upper horizontal tube 20 of the base frame. The pins are insertable through a pair of aligned holes 24 in opposed side walls of each tubular upright (only one hole 24 visible in Figure 3) so as to pass through selected holes of a corresponding series formed through each telescopically received vertical support member. The cross member can thus be secured at the desired height. The trestle base also includes a pair of feet 16, one attached to each upright 12, extending transversely of the cross member 18, so that the trestle will stand upright on level ground. One of the vertical support members has an upward extension 13 that reaches above the cross member 18 to provide a support post for platform guard rails (not shown). The opposite end of the cross member 18 is provided with a socket 15 in which the lower end of a removable guard rail support post (not shown) can be received.

The stabilising prop 10 shown in the drawings has an upper portion 2 telescopically received within a lower portion 3, but the reverse is equally permissible, i.e. the lower portion 3 could be slidably disposed within the upper portion 2. The upper portion and lower portion shown in the particular embodiment are formed from square sectioned steel tube. However the stabiliser is not restricted to this arrangement and any other suitable configuration or shape of variable length prop is permissible (for example props having non-coaxial relatively slidable upper and lower parts, or upper and lower parts lockably securable together at an angularly adjustable elbow). The upper portion 2 is slidable into the lower portion 3 as shown. Although non-circular tube sections are preferred so as to maintain alignment between locking mechanism components as further described later on, it is also possible to - use round sectioned tubes.

The lower portion 3 comprises a foot 4 formed from a flat rectangular plate attached at its lower extremity by welding or any other suitable conventional means. The underside of the foot 4 provides an enlarged load spreading surface which reduces the tendency of the .prop to sink into soft ground. The plate may be provided with one or more apertures (not shown) through which stakes can be driven, to secure the lower end of the prop to the ground. This combats any tendency for the foot to slide outwardly away from the trestle as the trestle is subjected to loads attempting to overturn it in the direction of the prop.

The telescopic arrangement comprises a releasable locking mechanism for adjusting and locking the stabiliser prop 10 to the desired length. In the illustrated embodiment the lower portion 3 comprises a series of holes spaced apart along the length of the leg. The upper portion comprises a pin 26b mounted within one end. The pin is biased in the outward direction, e.g. by a bow spring 98 secured to the interior of the upper portion 2 by a tack weld 100, or simply braced against the opposite interior wall of the tube. The outer end of the pin 26b protrudes through a guide hole 28 formed one at the end of the upper portion 2. The lower end of the upper portion 2 having the pin 26b is disposed within the lower portion 3 and is used for adjusting the length of the_. stabiliser prop 10 by selective engagement of the pin 26b in one of the holes 30. Disengaging the locking mechanism e.g. for prop length adjustment involves compressing the bowspring 98 by manually depressing the pin out of engagement with the hole 30. The outer end of the pin 26b can be rounded to allow the upper and lower portions to easily slide relative to each other.

The releasable locking mechanism for adjusting the height of the stabiliser is not restricted to this embodiment and other releasable locking mechanisms which permit the length of the stabiliser prop to be varied and locked in a desired position can be used. For example the pin need not be permanently attached to the prop upper or lower portion and can be a separate removable pin receivable in holes formed in the prop upper portion and lower portion, the holes being brought into registration as the prop is adjusted to the desired length. Figure 1 shows the stabiliser attachment extended to the point where the foot contacts and rests on the ground.

A further pin 26a again spring biassed e.g. by an arrangement similar to that used with the pin 26b, is preferably provided at the other (upper) end of the prop upper portion 2 for securing the stabiliser prop 10 to the upright 12 of the builder's trestle 14. The stabiliser prop 10 in the illustrated embodimentis releasably secured within a socket .50 secured to or formed integrally with the builders' trestle 14, by engagement of the pin 26a in a hole 34. As shown in Figures 2 and 3 the socket 50 is secured (e.g. by welds 32) to the tubular upright 12, at an angle so that the stabiliser prop when installed is extendible outwardly and downwardly from the builders' trestle to the ground.

In a variant of the illustrated embodiment, several sockets may be provided at spaced angular positions around the axis of the tubular upright or in other positions on the trestle 14, so that the prop extends outwardly and downwardly from the trestle in other directions, for example in a vertical plane transverse to the cross member 18. _. Several props may be used simultaneously, extending in different directions at one or both sides of the trestle, in contrast to the single prop shown at each side of the trestle in Figure 1. One or more of the sockets may be mounted to the trestle 14 so as to pivot about a vertical axis, thereby allowing the prop to extend from the trestle at any point along an arc in the horizontal plane. One, more or all of the described sockets may be replaced by any other suitable fastening means for the prop, for example a spigot received within a socket on (e.g. a tubular part of) the prop. That is to say that the stabiliser prop of the present invention may be releasably secured to the vertical support member of the builders' trestle by any suitable means, preferably although not necessarily one that allows quick and easy fitment and removal.

Figure 6 shows a further modification which may be particularly useful when the ground offers little resistance to outward movement of the foot 4 as the trestle begins to overturn in the direction of the prop 10. This may be for example where the trestle and prop are used on a smooth, hard surface. A cross brace 52 is formed from steel bar of U-shaped channel section. The base of the channel is cut away at one end to form a pair of ears 54 (only one visible in Figure 6). A pin 56 passes through the ears 54 and through the prop upper portion 2 to pivotally mount the cross brace on the prop 10. The cross brace 52 has a laterally projecting tongue 58 at its distal end, for latching engagement in a socket 60 welded or otherwise attached to the tubular upright 12 or at another suitable position on the trestle. Once the tongue 58 is dropped into the socket 60, it is held there by gravity. A rod, tube, cable, chain or the like having a hook or similar fitment at its distal end for engagement with the trestle, may be substituted for the cross brace shown in Figure 6. Additionally or alternatively, the foot underside may be covered with rubber or a. similar high friction - material.

Claims

CLAIMS:

1. An auxliary stabilising prop for a builders' trestle, having an end attachable to the trestle and another end engageable with the ground so that in use the prop may be attached to the trestle extending outwardly of a load bearing base of the trestle and braced between the trestle and the ground, characterised in that the length of the prop between the ends is adjustable.

2. An auxiliary stabilising prop as defined in claim 1, in which the ground engageable end of the prop comprises a foot.

3. An auxiliary stabilising prop as defined in claim 2, in which the foot comprises a load spreading pad.

4. An auxiliary stabilising prop as defined in claim 2 or 3 in which the foot is fixed to the prop at a fixed angle for engagement with the ground.

5. An auxiliary stabilising prop as defined in claim 2 or 3 in which the foot is adjustably mounted, with respect to the rest of the prop so that it can squarely engage the ground.

6. An auxiliary stabilising prop as defined in any preceding claim, in which the length of the prop is telescopically adjustable.

7. An auxiliary stabilising prop as defined in claim 6, in which inner and outer parts forming a telescopic mechanism may be selectively secured together in a variety of relative longitudinal positions by releasable locking means.

8. An auxiliary stabilising prop as defined in claim 7, in which the releasable locking means comprise a latch member secured to one of the inner or outer parts, and receivable in any selected one of a series of detents provided in the other of the inner or outer parts.

9. An auxiliary stabilising prop as defined in claim 8, in which the latch member comprises a spring loaded ball or pin attached to one part, and the detents comprise a series of apertures formed in the other part.

10. An auxiliary stabilising prop as defined in any preceding claim, in which an upper, end of the prop is attachable to the trestle by a spigot and socket connection.

11. An auxiliary stabilising prop as defined in claim- 10, in which the spigot and socket are interengageable by axial movement of the prop.

12. An auxiliary stabilising prop as defined in claim 10 or 11, in which the spigot is secured in the socket by releasable latch means.

13. An auxiliary stabilising prop as defined in claim 12, in which the releasable latch means comprise a spring loaded ball or pin attached to one of the spigot or socket and engageable with a detent provided in the other of the spigot or socket.

14. An auxiliary stabilising prop as defined in any preceding claim in which a cross brace is provided above the prop length adjustment means and which in use extends between the prop and the trestle.

15. A builders' trestle comprising an auxiliary stabilising prop as defined in any preceding claim,

16. A builder's trestle as defined in claim 15 comprising a platform supporting cross member, in which the auxiliary stabilising prop extends outwardly from the trestle and platform beyond an end of the cross member.